Blades boss Wilson is looking to strengthen his squad following the departure of leading goalscorer Nick Blackman to Reading and is close to signing former Scotland international Barry Robson, who left Vancouver Whitecaps earlier this month.
Wilson revealed he had been keen to bring Charlton's Wright-Phillips, but had cooled his interest due to finances.
"We remain hopeful of realistically bringing in one or two players before Friday's game (against Coventry)," Wilson said.
"Bradley Wright-Phillips was on our radar, but isn't anymore and that's because of costings.
"We have to be realistic and we can't bring players in who will take us over the Salary Cost Management Protocol (SCMP).
"There is nothing is the rumours about Mark (Duffy) of Scunthorpe United, we have our wide players already at the club and Lee (Williamson) was tremendous for us in my time here, but times have moved on and so has Lee."